Process of joining or uniting metallic sheets



Dee, 1957 E. G. BIANCA ETAL 2,8fl5,5

PROCESS OF JOINING OR UNITING METALLIC SHEETS Filed March 12, 1957 5 Sheets-Sheet l EDOARDO G. BIANCA KARL DIEBOLD INVENTORS ATTO R NEY 157 E. G. BIANCA ETAL 2,8155% PROCESS OF JOINING OR UNITING METALLIC SHEETS Filed March 12, 1957 3 Sheets-Sheet 2 EDOARDD G. BIANCA WKARL DIEBOLD HNVENTORS ATTORNEY W57 E. G. BIANCA ETAL yfiwfi PROCESS OF JOINING OR UNITING METALLIC SHEETS Filed March 12, 1957 3 Sheets-Sheet 3 EDUARDO G. BIANCA WXRL DIEBOLD INVENTOWS ATTORM EV United States Patent PROCESS OF JOlNING R UNITING SHEETS Edoardo Giuseppe Bianca, Zollikon, and Karl Diebold,

Kilchberg, Switzerland 1 Application March 12, 1957, Serial No. 645,422

4 Claims. (Cl. 29-505) METALLIC Our invention relates to a process of joining or uniting For instance it is possible to employ metallic sheets. this process in uniting the overlapping edges of tubularly shaped metallic sheets in order to produce tubular masts or poles.

A process aiming at'the same purpose is known in which the sheets are united by pairs of reciprocally enbetween said openings, vaulting said straps out of the sheets plane, inserting 'or fitting the seams of the two metallic sheets into each other in order to form at least one tubular channel constituted alternately by the vaulted straps of said first sheet and by the vaulted straps of said second sheet, introducing loosely a metallic locking-core 3 into each of the channels, flattening finally the complete seam by beating or pressing and simultaneously forcing the locking-core into a wave-like shape not protruding from the seam.

The seam, although weakened to some extent'by the openings cut out is reinforced by the locking core to such an extent as to approach the full strength of thesheet.

In the accompanying drawings we have illustrated a few examples of the process, but it will be understood that changes and alterations may be made in difierent applications without departing from the principles of the invention. 1

The figures show:

Fig. 1: an illustration of the overlapping edges of two metallic sheets with openings and straps ready for fitting together, as well as the locking-core.

Fig. 2: a plan view of the two sheets inserted into each other.

Fig. 3: a cross section of the inserted parts with the locking-core introduced.

Fig. 4: a cross-section of a finished seam built up by the parts shown in Figs. 1-3.

Fig. 5: an illustration of a second example.

Fig. 6: the two parts of the seam of the second example fitted into each other.

Figs. 7 and 7a: cross-sections of seams of the second example after introducing the locking-core but prior to flattening.

Fig. 8: a longitudinal section of seam according to analogousto Figs. 3 and 4, with an alternative type of locking-corn v As shown in Fig. l, the openings 1 and 2 cut out of the sheets to be united 3 and 4 in order to form straps 5 and 6. Straps 5 of sheet 3 are all vaulted out toward one side whilst straps 6 of sheet 4 are all vaulted into the opposite direction relatively to the former. The shaping of the straps is done preferably in such a way as to form shoulders 5a respectively 6a at the roots of the straps of a height corresponding approximately the thickness of the sheet. The width (measured in the direction of the seam) of the openings 1 and 2 is at least equal to the width of the straps 5 and 6 in order to permit an easy passage of the straps through the openings whenthe seam is fitted together. Straps 5 and 6 are preferably provided on their sides with arch-like or rectangular recesses 5b and 6b in order to ofier space for the passage of the locking core after flattening the seam. a

-' When prepared as described, the sheets 3 and 4 are inserted into each other by passing straps 5 of the upper sheet (in the drawing) down through the openings of the lower sheet, and simultaneously straps 6 of the lower sheet up through the openings of the upper sheet so that each strap passes through and beyond the other sheet. The marginal strip 7 of sheet 3 comes to match with sheet 4, respectively strip 8 with sheet 3. Thus a tubular channel is formed which is constituted alternately by a strap 5 of sheet 3 and a strap 6 of sheet 4. A metallic locking core is then inserted into said tubular channel. This may be done either by pushing it in, or, for very long seams, pulling it through by means of a wire previously inserted and attached to said lockcore. This procedure is indicated equally where a closefitting core is to be used or where small irregularities in the shape of the straps might render it ditficult to push the core through. a

The shape of the locking-core is adapted to the shape of the channel and its cross-sectional area in proper relation to the space it has to fill out after flattening the seam. It is preferably of a softer and more ductile material than the sheet in order to fill in completely the voids formed by the openings 1 and 2 and by the recesses 5b and 6b, as well as permit easy formation of the wave.- like shape during flattening of the seam. This pressing or beating will in any case produce a hardening and strengthening effect on the material of the core, and

should the final resistance be lower than that of the sheets, the diiference may be compensated by choosing 'an appropriate width of the core. The final flattening of the seam by heating or pressing is preferably done by proceeding from one end of the seam to the other, or from the center towards the extremities. This will allow the core to pull in the length needed for forming the waves, instead of causing a plastic elongation. By this process a fiat, even and strong connection of the sheets is obtained.

The basic process may be varied in practice in many ways. The solid, plastic type of core is preferably of lenticular or elliptic cross section, but may also be flat, and, in all cases, hollow instead of solid. correspondingly the recesses 5b, 6b may be round or angular, with or without shoulders in the corners; straps 5, 6 may be exactly in a right-angle position to the axis of the seam or they may be oblique to the same; shoulders at the roots of the vaults of the straps may be substituted by a smooth transition, all without affecting the basic principles.

Another example of practical application of this invention is shown by Figs. 5 and 10. Straps 11, 12 of sheet 10 and straps 16, 17 of sheet 14, are formed respectively by the intervals between openings disposed in rows, as in the former example. The width of said openings,

. material.

however, is only approximately equal to the thickness of the locking core, and the straps are preferably several times wider than said openings. The straps of each row (and: in eachsheet) are then vaulted alternately down.- wards and upwards (in the drawing) and furthermore the straps 11 of the lowerv sheet are vaulted. down more deeply by about one sheets thickness than straps: 12 are vaulted up. Correspondingly straps. 16 of the upper sheet 14. areless deeply vaulted down than straps 17 are vaultcdup. In addition,. the deeper straps 11, 17 are longer. by about two-sheets thicknesses than the-shallower straps 12,- 16- This permits to fit the two sheets 10 and 14 into each other by superposing individually a deep and a shallow strap, each successive pair 11-16 and 121Z beingvaultedv out to a direction opposite to the preceding one.

A, tubular channel is. thus. formed. as in the preceding example, but it isbuilt up. by elementsconsisting of double, superposed straps, each of. whichbelongs. to a different sheet. The lockingelement and its application, .as wellas the finishingofi thezseam. areexactlythe same as-describe'd in the preceding example.

This type is recommended. where very high. scams-trengthisrequined. By proper choice of. shapes; dimensions and materials it is possible to obtain a strength very near to unity relatively to the full sheet, i. e. superior to welded. seams.

Here again, many executional details may be varied without affecting the basic principles. Particularly the following pointsare susceptible to be modified: The roots of the straps=may be shaped in a smooth and easy transition, a'sshown bythe dotted linesin Fig.7 (left hand side) without any'shoulders,,employing a core? with lenticular cross section; the connection may beconstituted by'more than one seamas-shown. in Figs. IOaand 10b, usingseveralicores 20a; the openings or slots 13, may either be in a rectangular position relatively to the seam asin Figs. 5, 6, 9a'and. 10a,,or may be oblique as 13,15,131), 15b in:Figs-. 9b and 10b. Lateral recesses in the straps are not required in this type, as'the slot-like openings themselves will. be properly dimensioned to I provide passage for the core. It hasbeen shown in practical. tests that the highest seam. strengthis. obtainedtwith this-type, employingslot-like openings oi a width equal or slightly inferior to the. thickness: oi. the core,,said slots.-being-,disposed. obliquely at such/an angle that williplace. one end of one slot in the same. rectangular alignment,. to the seams axis, as the beginning, ofthe following. slot, as showniin Fig. 9b, since this permits the maximummltilisation of-the sheara strength .ofthe core, without'creating local pressures above the yield point orzshear point ofthe metal employed. In. double seams distance. betweenslotsemust bedoubled in. orde'rtt-o take advantage: of thislayout, as virtually the slot-hastbeensubdivided into two.

Astor shapeand materialofthe lockingacorei 20, a, the same applies here assaid for the previous'example.

A further and inpractice very useful and important variation indetail consists in'employing a laminated-lockingcoreas shown-in Figs. 7a,- ll and 12, which is applicaable in all cases. The core is formed by two'ori more strips 20,.9a, preferably of hollow shape such as.to;match closely theinner shapeof the tubular channelformed by the straps 12- and 16, respectivelyS and: 6. Each'lofsaid stripsoverhangs slightly on oneof the edges thus facilitatinga tight fit and complete filling up of-the openings. The lamination offers less resistance to. the wave-like'formation during flattening and allows the useof harder. and stronger The arched, hollow shape of the. strips-makes themexpand laterally. when .flattened, .exactlyain'z the-same way as the straps 11 12, 16, 17, resp. 5, 6 themselves, thus producing a completely sealed seam by completely filling out the openings, even with a comparatively hard material for the core. In this case, the sum of the thicknesses of the laminations is preferably approximately equal to the thickness of the sheets to be united.

The actual mechanica'l operations of producing seams as described are straightforward and can be carried out by" existing and well' known. machinery and tools.

What we claim as new and desire to secure by Letters Patent is:

1. In a process.ofijoiningmetallicsheets by a seam-like connection, cutting out at least one row of openings in each metallic sheet in ord'er'to form series of straps, disposed transversely' to the. seam, between said openings, vaulting said straps out of the sheets plane, inserting or fitting the seams of the two metallic sheets into each other in order to form at least one tubular channel constituted alternately byxthevaulted straps ofsaidfirst sheet and by the vaultedstraps of saidsecond sheet, introducing loosely'a metallic: locking-core into each of the channels, flatteningfina'lly the complete seam by beating or pressing and simultaneously forcing the locking-core into a wave-like shape: not'protruding from the seam.

2; Inzapprocess: of joining metallic sheets by" a seamlike' connection, cuttingout at least one row of openings inleach metallic sheet in' order to form series of straps, disposed transversely to the seam, said openings possessing aawidth-measured indirection of the seam--at least equal to the width of the straps formed by their intervals, vaulting-said straps ofeach-rowof each sheet out to one side only,.inserting. then the seams into each other by passingeach vaultedstrap of one sheet through the corresponding opening of the other sheet-until the two sheets mat'ch together, in order. to form at least one tubular channel constituted alternately by the-vaulted straps of one. sheet and the vaulted straps of the'other' sheet, inserting thenlooselyz'a metallic locking-core into said tubular channel, flattening'finally'the complete seam by heating: or. pressing and simultaneously forcing. the lockingcore'into a wavelike shape not protruding from the seam.

. 3; In a. process. of joiningxmetallic sheets by a seamlike connection,cuttingout at least one row of openings in each metallic sheet in order to form series of straps, disposedtransversely.to the seam, said openings possessing a widthern'easured in: direction of the: seam-smaller than the:widthaoftthe straps'rformed by their intervals, vaulting outisaid. strapsof each rowalternately to one side and to the'opposite side, fittinglthen the seams intoeach other'by placing alternate:individual straps of each sheet into" thescorresponding hollows of straps of the other sheet vaulted in the same direction, in order to produce at least one tubular channel formed alternately by the-superposed vaulted:straps1of both. sheets, inserting. then loosely a metallic locldng-zcore'into said tubular channel, flattening finally the completez'seam by beating or pressing'and simultaneously forcingthe locking-core into a wave-like shape not protruding from the seam.

4:. Processasclaimed under- 1,'.in which each of said locking cores is formed by at least two separate, transversely vaulted (hollow): strips, introducing each pair of said strips into said tubular channel with their concave sides turned=towards each other. 

